Integral to every Burns Night, marked by a recitation of Burns's own "Address to a haggis", is the haggis. The "great chieftan o'the puddin'-race" is virtually Scotland's national dish – as quintessentially Scottish, certainly, as heather, kilts, bagpipes, porridge, whisky and deep-fried Mars bars.

Except it isn't. A food historian, Catherine Brown, has discovered that the haggis is English: the first written record of it appears in a book by the 17th-century author Gervase Markham over a century before any Scottish reference to haggis; in The English Huswife, he notes the widespread popularity of the dish in England. The haggis was later successfully exported to Scotland, Brown avers. This is a view hotly disputed by some north of the border, who are unwillling to relinquish Scotland's national claim to the haggis and accept it as a culinary mongrel.

To others, it might seem ironic that there would be any wish whatsoever to assert ownership of a steaming concoction of sheep's offal, oats and spices stuffed (by tradition) into a sack made of sheep's gut, but the national identity of the haggis is being hotly debated – especially on a day when new immigration rules will introduce a test for would-be citizens of whether they have participated in any "unBritish" activities.

So which is it with the haggis – "unEnglish" or "unScottish"? And do you share Burns's enthusiasm for those "gushing entrails bright" – "O what a glorious sight, / Warm-reekin, rich!"